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Author: Barrett Stone Baldwin
Publisher:
Published: 1953
Total Pages: 46
ISBN-13:
DOWNLOAD EBOOK →Linearized compressible-flow analysis is applied to the study of wind-tunnel-wall interference for subsonic flow in either two-dimensional or circular test sections having slotted or porous walls. Expressions are developed for evaluating blockage and lift interference.
Author: James D. Keller
Publisher:
Published: 1971
Total Pages: 26
ISBN-13:
DOWNLOAD EBOOK →A numerical method is presented for calculating the boundary-induced interference at subsonic speeds in wind tunnels of rectangular cross section with slotted or perforated walls. The slot width or wall porosity can vary throughout the test section. The interference can be computed at any point in the test section. The model can be any configuration and can be located anywhere in the test section. Several examples are given, and comparison is made with other methods were available.
Author: B. F. R. Ewald
Publisher:
Published: 1998
Total Pages: 578
ISBN-13:
DOWNLOAD EBOOK →This report was compiled by an international team of wind tunnel wall correction experts. It presents the present state of the art in wind tunnel wall corrections with a special emphasis given to the description of modern wall correction methods based on Computational Fluid Dynamics. This AGARDograph was planned by the AGARD Fluid Dynamics Panel to be a modern sequel of the successful AGARDograph 109 "Subsonic Wind Tunnel Wall Corrections", which was published in 1966. AGARDogaph 109 is still valid and continues to be used to provide wall corrections in many wind tunnels. Nevertheless, in the thirty two years since the publication of AGARDograph 109, much work has been done on the subject, and the influence of the new tool of numerical fluid dynamics was so strong, that a sequel to AGARDograph 109 was considered to be necessary.
Author: C. F. Lo
Publisher:
Published: 1969
Total Pages: 129
ISBN-13:
DOWNLOAD EBOOK →Equations and charts as obtained by theoretical analyses are presented for the evaluation of corrections which must be applied to test data as obtained from wind tunnels because of the presence of the test section boundaries. Results are presented for two-dimensional, circular, and rectangular tunnels with boundaries of the completely closed, completely open, slotted, or perforated variety. Interference factors accounting for the direct effects of model and wake blockage on the longitudinal velocity and of model lift on the upwash velocity are enumerated. In addition, consideration is given to the variation of the longitudinal and vertical velocity components along the tunnel axis leading to buoyancy and streamline-curvature corrections. (Author).
Author: Travis W. Binion
Publisher:
Published: 1971
Total Pages: 72
ISBN-13:
DOWNLOAD EBOOK →The investigation reported herein is the experimental portion of a unified theoretical and experimental search for a slotted wind tunnel wall configuration with minimal interference for conventional and V/STOL models. It is shown that theory and experiment are in excellent agreement for the classical case provided an appropriate expression is used to relate the wall geometry to the boundary condition. Classical data correction equations are not appropriate for the V/STOL case, however. An additional term, not predicted by theory, is needed to account for changes in the jet wake. Geometric parameters which influence the wall interference quantities are indicated. Wall configurations are shown which will produce interference-free force data to a jet-to-free-stream velocity ratio of 4.5. (Author).
Author: United States. National Advisory Committee for Aeronautics
Publisher:
Published: 1958
Total Pages: 1216
ISBN-13:
DOWNLOAD EBOOK →Author: E. M. Kraft
Publisher:
Published: 1976
Total Pages: 84
ISBN-13:
DOWNLOAD EBOOK →The wind tunnel boundary interference at transonic speeds on a thin airfoil in a two-dimensional perforated-wall wind tunnel was determined. The interference was found by applying an integral equation method to the nonlinear transonic small disturbance equation including embedded supersonic regions with shock waves. The kernels of the ensuing integral equation were replaced by series approximations, and the integrals were evaluated in closed form. The iterative technique used to calculate the interference from the integral equation method is shown to converge rapidly, and the computing time for the integral equation method is typically an order of magnitude less than present numerical methods. As a special case, the integral equation method for a thin airfoil in free air was also examined. It was found that the introduction of a novel influence function yields, for the first time, a self-contained integral equation for a lifting airfoil. In addition, a systematic study of the classical assumption used to simplify the integral equation shows that the integral method can provide solutions in good agreement with results from the numerical methods.
